Easy method:

Schedule the workflow to run everyday and have a condition in you worklow to check if today is the other August 1. You can use the token calculator to check if the year is an odd or even number with this formula:

ISODD(YEAR(%(Date)))

Script method:

Set an initial date in your starting rule and have a an SDK Script activity in your workflow update the date in your starting rule.

Sample Script:

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Data.SqlClient
Imports System.Text
Imports Laserfiche.RepositoryAccess
Imports Laserfiche.Workflow.Objects 'Dont forget to add in Reference in the project explorer

Namespace WorkflowActivity.Scripting.SDKScript
    '''<summary>
    '''Provides one or more methods that can be run when the workflow scripting activity is performed.
    '''</summary>
    Public Class Script1
        Inherits RAScriptClass104
        '''<summary>
        '''This method is run when the activity is performed.
        '''</summary>
        Protected Overrides Sub Execute()
           'Create connection to workflow server
           Dim conn as Laserfiche.Workflow.WorkflowConnection = Laserfiche.Workflow.WorkflowConnection.CreateConnection("localhost","MyWF")
           'Retreive starting rule
           Dim startRule as Laserfiche.Workflow.Objects.ScheduledStartingRule = conn.Database.GetStartingRule("MyRuleName")
           'Get XML for rule
           Dim xmlRule as String = startRule.ScheduleXml
           'Get current year
           Dim currentYear As Integer = System.DateTime.Now.Year
           'Set next run in 2 year
           Dim nextYearSchedule = currentYear+2
           'Update XML
           xmlRule = xmlRule.Replace(currentYear.ToString,nextYearSchedule.ToString)
           'Update rule
           startRule.ScheduleXml=xmlRule
           startRule.Update
        End Sub
    End Class
End Namespace

Thanks.